Trimmer capacitor with direct travel mechanism



Dec. 28, 1965 H. SEIDEN 3,226,616

TRIMMER CAPACITOR WITH DIRECT TRAVEL Filed Aug. 22, 1962 MECHANISM JG INVENTOR.

bly is formed of a piston -a piston'shell and secured to the 3 226 616 TRIMMER 'CAPACITQIR vvrrn Dinner TRAVEL MECHANISM Hugo Seiden, Brooklyn, NY, assignor to IE1) Electronics York Filed Aug. 22, 1362, Ser. No. 218,753 3 Ciaims. (Cl. 317-249) Corporation,Brooklyn, N.Y., a corporation of New This application relates to a novel direct travel mechanism for reactors and is more specifically an improvementof my copending-application Serial No. 183,512 filed March 29, 1962 assigned to the assignee of the present invention.

More specifically, the reactor of the present invention has an improved piston arrangement which prevents in- '-ternal"s'tresses in the body of the piston shell and there- .Thus, .a. special extruded shape or.precision fine threading of the piston Which would automatically introduce stress concentration in the piston are eliminated and the manufacturing procedure is simplified.

It is therefore, a primary object of this invention to provide a novel direct travel mechanism for reactors.

A further object of this invention is to provide a novel direct travel mechanism which avoids internal stress in the body of the piston shell.-

Another object of this invention is to provide a novel reactor which has improved electrical stability.

Another object of this invention is to simplify the manufacturing techniques required for forming a direct travel mechanism.

These and other objects of this invention will become apparent from the following description when taken in connection with the drawings, in which:

FIGURE 1 shows a cross-sectional view of a reactor constructed in accordance with the present invention when taken through the lines 1-1 of FIGURE 2.

FIGURE 2 is a cross-sectional view of FIGURE 1 taken across the lines 2-2 in FIGURE 1.

FIGURE 3 is a cross-sectional view of the piston assembly of FIGURES 1 and 2 and is taken across the lines 3-3 in FIGURE 4.

FIGURE 4 is a plan view of the left-hand end of the piston assembly of FIGURE 3.

FIGURE 5 is a cross-sectional view of a modified piston assembly and is taken across the lines 55 in FIGURE 6.

FIGURE 6 is a side plan view of the left-hand side of FIGURE 5.

Referring now to FIGURES 1 through 4, I have illustrated therein a reactor of the type shown in my copending application Serial No. 183,512, filed March 29, 1962. Generally, the reactor is comprised of a bushing 10 having an external thread 11 and a mounting flange 12.

The bushing has two extending portions 13 and 14 (FIGURE 2) which are defined by slots 15 and 16. The bushing 10 receives an adjusting screw or driving screw which has two enlarged sections 21 and 22 that capture an O ring 23 to hermetically seal the left-hand end of the unit.

A pair of Belleville washers 24 and 25 are captured between enlarged portion 22 and a torque adjusting screw 26 which is threaded into the internal thread 27 in bush- United States Patent 0 .tube portion 41 and an outer ing10. The torque adjustment screw 26 may have tool receiving means 28 and 29 to permit rotational adjustment thereof. The end of screw 20 extends through an opening in screw 26 to present a tool receiving slot 30 to an operator whereupon the adjustment screw 20 can be rotated with respect to bushing 10. The adjustment screw 20 extends to the right and receives an internal tension nut 31 and passes into threaded opening 32 of the piston assembly 33 which is best shown in FIGURES 3 and 4 and will be referred to in more detail hereafter.

An anti-backlash helical spring 34 is then captured between nut 31 and the left-hand surface of piston assembly 33, where the nut 31 has a portion thereof such as portion 311:, extending into slot 16 to prevent rotation of the nut. Thus, as screw 20 isrotated, the nut 31 will be the same distance away from piston assembly 33 to maintain a constant biasing force between piston assembly 33 and screwZO.

The entire assembly is then coaxiallycontained within a dielectric tube 40, which is formed of an inner glass glass tube portion 42. The dielectric tubes 41 and 42 are then secured to flange 12 as by soldering at soldered region 43.

The outer portion of the inner glass tube 41 is metallized to form an electrode 44 which cooperates with piston 33 during the operation of the device. A second metal lized layer 45 is then carrieron the outer surface of glass tube 42 and is electrically connected to the conductive ends plate 46 which is insulated from the inner electrode 44 by the insulation washer 47. Washer 47 also prevents accidental contact between piston 33 and plate 46.

The construction of the novel now be described with particular reference to FIGURES 3 and 4. As shown in FIGURES 3 and 4, the assembly is formed of two sections; a piston guide section 50 and a piston shell section 51.

The shell section 51 is rigidly secured to guide section 50 by spinning the end portion 52 of guide 53 over the inwardly bent end of shell portion 51. Alternatively, the two outer ends could be soldered together or could in general be secured to one another in any desired manner where internal stressing of the shell 51 is avoided.

The left-hand end of shell portion 51 has then extending tabs 54 and 55 which are bent downwardly as shown in the figures. The tabs 54 and 55 as best shown in FIGURE 1 for the tab 55 then rides in slots 15 and 16 respectively, which separate the extending bushing into portions 13 and 14 as shown in FIGURE 2.

Thus, a simplified guide is provided which will prevent rotation of shell 51 during the adjustment of capacitor of screw 41. This gives the device a high degree of stability.

It will be noted in FIGURES l and 2 that the tubular bushing extensions or extending portions 13 are spaced from the interior of inner glass tube portion 41 by some predetermined distance which is substantially equal to the radial thickness of piston shell section 51. Moreover, the inner and outer piston shells or the piston guide sect-ion 5'0 and piston shell section 51 are radially spaced from one another by second predetermined constant radial distance which is substantially equal to the radial thickness of the bushing extension 13 and 14.

While the embodiment of FIGURES 1 through 4 illustrate the guide ears as extending from piston shell 51, an alternative embodiment is shown in FIGURES 5 and 6 where the guide ends extend from the section 50.

Thus, in FIGURES 5 and 6 where all of the components similar to those of FIGURES 3 and 4 have given similar identifying numerals, the piston guide section 50 is provided with extending tabs and 61. It can be readily understood that the piston of FIGURES 5 and 6 piston assembly 33 may can be directly used in the reactor of FIGURES 1 and 2 to assure the avoidance of internal stress in the body of the piston shell.

Moreover, the novel construction of FIGURES 1 through 6 generally permit simplicity in manufacturing and improved. electrical stability since special extruded 'shapes and precision fine threading of the piston shell is avoided.

Although I have described preferred embodiments of I my novel invention, many variations and modifications will now be obvious to those skilled in the art, and I prefer therefore to be limited not by the Specific disclosure herein but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A reactor comprising a main I support bushing, a tubular bushing extension connected to and extending from one end of said main support bushing, a tubular dielectric cylinder surrounding said tubular bushing extension and being connected to and extending from said one end of said support bushing, a piston assembly contained within said tubular dielectric cylinder, and rotatable adjustment means connected to said piston assembly for moving said piston assembly with respect to said tubular dielectric cylinder; said tubular bushing extension being radially spaced from the interior of said tubular dielectric cylinder by a first predetermined distance; saidpiston assembly comprising an outer piston shell and an inner piston shell concentric with said outer piston shell; said outer piston shell and sai'd iriii'el' piston shell being secured together at one end of said outer and inner piston shells; said inner piston shell including threaded means threadably receiving said rotatable adjustment means; said tubular'bushing extensional-raving a longitudinal slot therein; one of said piston shells having a radially extending integral portion extending therefrom and into said slot to prevent rotation of said piston assembly; said inner and outer piston shells being radially spaced from one another by asecond predetermined constant radial distance; saidouter piston shell having a radial thickness equal to said first predetermined distance and being received between said dielectric tube and said tubular bushing extension; said" tubular bushing extension having a radial thickness equal to 'said second predetermined distance andbeing' received b'etween said inner and outer piston. shells.

2. The device substantially as -set forth in' claim 1 wherein said outer'piston shell has a radially inwardly extending portion extending into said longitudinal slot.

3. The device substantially as set forth in claim 1 wherein said inner piston shell has a radially outwardly extending portion extending into said longitudinal slot.

7 References Cited by the Examiner V UNITED STATES PATENTS V JOHN F. BURNS, PrimaryExaminer; 

1. A REACTOR COMPRISING A MAIN SUPPORT BUSHING, A TUBULAR BUSHING EXTENSION CONNECTED TO AND EXTENDING FROM ONE END OF SAID MAIN SUPPORT BUSHING, A TUBULAR DIELECTRIC CYLINDER SURROUNDING SAID TUBULAR BUSHING EXTENSION AND BEING CONNECTED TO AND EXTENDING FROM SAID ONE END OF SAID SUPPORT BUSHING, A PISTON ASSEMBLY CONTAINED WITHIN SAID TUBULAR DIELECTRIC CYLINDER, AND ROTATABLE ADJUSTABLE MEANS CONNECTED TO SAID PISTON ASSEMBLY FOR MOVING SAID PISTON ASSEMBLY WITH RESPECT TO SAID TUBULAR DIELECTRIC CYLINDER; SAID TUBULR BUSHING EXTENSION BEING RADIALLY SPACED FROM THE INTERIOR OF SAID TUBULAR DIELECTRIC CYLINDER BY A FIRST PREDETERMINED DISTANCE; SAID PISTON ASSEMBLY COMPRISING AN OUTER PISTON SHELL AND AN INNER PISTON SHELL CONCENTRIC WITH SAID OUTER PISTON SHELL; SAID OUTER PISTON SHELL AND SAID INNER PISTON SHELL BEING SECURED TOGETHER AT ONE END OF SAID OUTER AND INNER PISTON SHELLS; SAID INNER PISTON SHELL INCLUDING THREADED MEANS THREADABLY RECEIVING SAID ROTATABLE ADJUSTMENT MEANS; SAID TUBULAR BUSHING EXTENSION HAVING A LONGITUDINAL SLOT THEREIN; ONE OF SAID PISTON SHELLS HAVING A RADIALLY EXTENDING INTEGRAL PORTION EXTENDING THEREFROM AND INTO SAID SLOT TO PREVENT ROTATION OF SAID PISTON ASSEMBLY; SAID INNER AND OUTER PISTON SHELLS BEING RADIALLY SPACED FROM ONE ANOTHER BY A SECOND PREDETERMINED CONSTANT REDIAL DISTANCE; SAID OUTER PISTON SHELL HAVING A RADIAL THICKNESS EQUAL TO SAID FIRST PREDETERMINED DISTANCE AND BEING RECEIVED BETWEEN SAID DIELECTRIC TUBE AND SAID TUBULAR BUSHING EXTENSION; SAID TUBULAR BUSHING EXTENSION HAVING A RADIAL THICKNESS EQUAL TO SAID SECOND PREDETERMINED DISTANCE AND BEING RECEIVED BETWEEN SAID INNER AND OUTER PISTON SHELLS. 